直角三角形中的比例关系探索
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①本范例演示直角三角形中边长与角度的比例关系,特别是与内切圆相关的几何性质。②涉及核心数学概念包括直角三角形性质、内切圆、勾股定理、三角函数、线性回归等。③作图要点:使用Segment、OrthogonalLine、Point、Angle、Intersect、Circle、Polygon等GeoGebra命令构建图形,并计算边长a、b、c及角度α、β、γ。④适合高中数学教学,用于探索和验证几何定理,增强空间想象能力。
GeoGebra 命令及参数
Segment(A_1, B) → aOrthogonalLine(B, a) → bPoint(b) → CSegment(B, C) → cSegment(A_1, C) → dAngle(A_1, B, C) → αOrthogonalLine(B, d) → eIntersect(e, d) → DSegment(B, D) → fAngle(B, D, A_1) → βCircle(D', Segment[D, A_1]) → gPoint(g) → ASegment(D', A) → hOrthogonalLine(D', h) → iCircle(D', Segment[D, B]) → kIntersect(k, i, 2) → B'Segment(D', B') → jSegment(A, B') → lAngle(A, D', B') → γPolygon(A_1, D, B) → poly1, b_1, a_1, d_1Polygon(B, D, C) → poly2, c_1, b_2, d_2Polygon(A, D', B') → poly3, b', a_2, d'Circle(D'', Segment[D, B]) → pPoint(p) → B''Segment(D'', B'') → mCircle(D'', Segment[D, C]) → qOrthogonalLine(D'', m) → nIntersect(q, n, 2) → C''Segment(B'', C'') → rPolygon(B'', D'', C'') → poly4, c'', b'', d''Angle(B'', D'', C'') → δAngle(D, A_1, B) → εAngle(B, C, D) → ζAngle(B', A, D') → ηAngle(D', B', A) → θAngle(C'', B'', D'') → ιAngle(D'', C'', B'') → κ